Pollution Of Heavy Metals In Soils And Effect On Safety Of Agro-products In Xuzhou Area

The paper discussed the impact of heavy metal pollution in xuzhou soil on agro-productions' quality. Soil samples and agro-products, which are most vegetables, were collected from 18 bases, and analysed for the concentration of Pb, Cd, Cr, Hg, As, Cu, Ni to estimate the pollution. We also discussed the relation between heavy metal content in agro-products and that in soil, including available content and activity index. Based on the results, we forecast the trend of the heavy metal content in xuzhou soil and its impact on the quality of agro-products, and test to establish an alarming system of the soil quality and agro-products' safety . Following conclusions were achieved:1.Compare with the background value,all the seven kinds of elements have some soil samples in the 18 bases exceed the soil background value, suggesting those bases have been polluted by heavy metal. Cd , Cr and Cu content exceed the 1st standard, especially the Cd content. All metal content in soil are under the 2nd standard. 2.The order of metal content in agro-products are as follows: tomato: Pb>As>Cd>Hg cucumber: As>Pb>Cr>Hg>Cd eggplant: As>Pb>Cr>Cd>Hg capsicum: As>Pb>Cr>Cd>Hg 3.The order of agro-products' enrichment capability on the heavy metal are as follows:Pb: celery>cauliflower > radish > burdock> yam>lettuce >tomato> eggplant> capsicum, cucumberCd: burdock>celery>radish>lettuce>yam>cauliflower>eggplant>capsicum>tomato> cucumberCr: radish >lettuce> celery > burdock >capsicum> eggplant> cucumber > tomato Hg: celery >caulifiower, yam> radish > burdock>cucumber> lettuce >eggplant, capsicum> tomatoAs: burdock>cauliflower > radish > yam>lettuce >eggplant> capsicum> cucumber> tomato> celery4.The quality of agro-products in xuzhou agriculture bases accord with the food sanitation standard. Very few element in specific exceed the standard in few base.5.There's evident correlation between the Cd> Hg, Pb content in xuzhou soil and the heavy metal content in products. The available metal content have no evident correlation with heavy metal content in products, so do the activity index.6.The analyse of soil heavy metal concentration show that in xuzhou Cd will probably be the first pollution in the following time. Suggesting Cd increase as the current rate,0.0077mg/kg.y,the Cd content in xuzhou soil will exceed the 2st standard in about 2053.Before that time, tomatoes field in that area all accord the food sanitation standard.